In her debut picture book, The Strangest Fish (Astra Young Readers, Sept.), award-winning fantasy author Katherine Arden (the Winternight trilogy and the Small Spaces Quartet series) follows a girl who wins a secretly powerful fish at the county fair. PW spoke with Arden about writing for very young readers and how her dog, Moose, inspires her fiction.

The Strangest Fish is your picture book debut. Why did you want to write a picture book?

One thing that’s important to me as a writer is taking unstructured time every day to open my notebook and play with new ideas. I usually do this before I get to work on my primary project. It is a satisfying and low-stakes way to start the day and, of course, leaves me with a repository of ideas that I can return to or discard. The Strangest Fish began in one of these notebooks. I had a playful idea about a girl and a magic fish, and when I started working on it, it coalesced quickly into a little story. That doesn’t always happen with my notebook ideas. It also had a distinctive voice. I don’t try and force a particular voice or style onto my notebook ideas, but in this case, I could tell pretty quickly that this was a story that would be for very young children. I also thought it would look amazing with illustrations. So I went ahead and typed up my handwritten text, edited it a bit, and, rather tentatively, gave it to my agent. He agreed that it was indeed a picture book, and I suppose the rest is history.

You’re a bestselling author who has written books in both the adult fantasy and middle grade spaces. How did the process of writing The Strangest Fish—in which you tackle the 48 age category—compare with writing those other books?

It’s really hard to compare writing a picture book with writing a novel. A picture book is an order of magnitude shorter, for one thing. It’s almost like flash fiction, and every word has more-than-usual weight, when you have fewer than a thousand of them. Also, doing a picture book requires collaboration with an illustrator, which was a new and wonderful experience for me. Zahra Marwan, who did the beautiful watercolors in The Strangest Fish, is so talented. And of course, the illustrator is a true collaborator, since the writer’s text is the basis for the illustrations, but the illustrations influence the editing and layout of the text. It’s a process of give-and-take that I found really interesting. I loved seeing my text come alive in pictures, and honestly, I think the illustrator does more and harder work than the author on a picture book and is just as, if not more, crucial to the book’s success.

The Strangest Fish has a whimsy that will appeal to readers of all ages, including your dedicated fan base. Do you ultimately see this as a book for both kids and adults? Why?

The Strangest Fish was definitely written for small children. But if I know anything about very young readers, it's that they ask for their preferred books about a million times, and I do hope that my text won’t utterly try an adult’s patience, even with repetition. I wrote this book to give pleasure to whoever picks it up, and I hope it does.

How does The Strangest Fish speak to the transformative power of unconditional love, and why is that message so important today?

In The Strangest Fish, my main character, Daisy, loves her pet fish fiercely even though, in the beginning, she isn’t even sure she wants him. But she has him and chooses to love and take care of him regardless. The power of generosity and kindness without any expectation of return is a common trope in fairy tales. Think of “The Frog Princess,” to give just one example. I think people have always understood the vital importance of teaching generosity and kindness to children via storytelling and what an important role kindness has in the creating of healthy families and communities. I feel like with The Strangest Fish, I am just coming at the end of a long storytelling tradition, in that sense.

The book is infused with delightful magical elements. What do you like about using magic to connect with readers?

I have always loved magic in stories. Fairy tales and wonder tales delighted me as a very small child, and then as a young reader. I hope that The Strangest Fish speaks to other children who are like I was, who love magic and who dream that maybe just maybe they will, like Daisy, find a water dragon to be their best friend.

Did you discover anything about yourself through writing this book?

I discovered that I was capable of writing a complete story of less than 1,000 words. I never had before, and it was very satisfying.

You have a pet dog named Moose. Did your relationship with your dog inspire any part of this unique fish story?

Moose is my Plott hound mix, and he inspires every story I write. He’s my constant writing buddy, and if I lack inspiration I stop what I’m doing and pet him or take him for a walk. It works every time. That’s the magic of loving the creatures in our lives. I guess I’m like Daisy in that way.